The Sky This Week, 2010 February 16 - 23

Digging out, zooming in...

Mars, imaged 2010 February 15, 03:39 UT

The Moon waxes in the evening sky this week, starting the week off as a slender crescent in the western twilight sky before quickly climbing to a point nearly overhead by the week’s end. First Quarter occurs on the 21st at 7:42 pm Eastern Standard Time. Look for Luna just two degrees east of the Pleiades star cluster on the evening of the 21st. By the 23rd she’s parked just about smack in the center of the Great Winter Circle.

As most regular followers of this feature probably know, the Washington DC area was hit with an unprecedented pair of snowstorms this past week. We’re still digging out from under nearly three feet of the white stuff, but what was written in the previous edition still holds true: the sky somehow takes on a special appearance when the ground is covered with snow. While we wait for the snow to melt from the domes of our telescopes or shovel out a patch of the front yard to set one up at home, the glimmer from winter’s evening beacons becomes more focused in the crisp night air. The inversion of cold air over the deep snow-pack stabilizes the “twinkling” of the stars, giving them a sharper, more color-saturated appearance. This also helps to sharpen the views of the Moon and planets through small to medium aperture telescopes, so if you own one it’s worth clearing that extra little patch of ground to set your up.

Over the past two weeks giant Jupiter has plummeted toward the horizon. On the 16th Old Jove lies only half a degree from brighter Venus just five degrees above the horizon some 15 minutes after sunset. This is an extreme test of binocular observing skills and requires a pristine sky and flat western horizon to sight, but it will be one of the closest planetary appulses of the year. Venus is gradually creeping higher into the evening sky, but if you miss Jupiter on this occasion you’ll have to wait for his emergence into the morning sky next month.

Mars is now a few weeks past opposition and he has begun to fade as the distance between his ruddy surface and Earth increases. The red planet’s already small disc has shrunk by some five percent from its mere 14.1 arcseconds at opposition, but the clear, steady air over the snowy landscape has improved the view of fine details on his distant face. I had one of my best views for the entire apparition a few evenings ago from the street in front of my house. Luckily the snow plow didn’t come that night!

Saturn finds his way into the sky by around 8:00 pm at week’s end, and by 10:00 pm his soft golden glow begins to clear the treeline in the southeastern sky. I caught my first glimpse of him for this year after I looked at Mars, and it was nice to be back on a relatively large target again. His overall appearance is similar to the view from last year with his rings presented at a nearly edge-on angle, but this year for the first time since 1995 we’re looking at their northern side. Hopefully by the time Saturn reaches opposition the snow will have melted from my yard and I can observe him in relative warmth!